The invention concerns a gear comprising: a truncated cone element (10) coupled to a drive shaft (12); a reduction element (20) whose axis of rotation is inclined relative to the axis of rotation of the truncated cone element (10) and engages with the latter; and an adapting gear (30) which engages with the reduction element (20) and is coupled to an output shaft. The reduction element (20) can slide along an outer periphery of the truncated cone element (10) in order to adjust the reduction ratio.
